Before the levosimendan intravenous injection the patients firs have an echocardiography to evaluate myocardial function, NT-proBNP. Subsequently, an arterial line is inserted and optimization achieved by using this arterial line connected to a ProAQT sensor system ( PULSION , Edwards). The system uses pulse wave analysis to assess several parameters including: stroke volume index (SVI), cardiac index (CI), systemic vascular resistance index (SVRI), cardiac power index (CPI).The levosimendan will be administered like a continues injection during 24 hours (0,1 mcg/kg/min) without initial dose. Following the optimization the patients will be transferred to the operating room in the next 3 days and will come back to the resuscitation and anaesthesia room where they will stay 24 hours more if there is no any complication.